The present invention relates to a novel fibrous material which is a rayon fiber containing fine particles of tourmaline and to a method for the preparation thereof. More particularly, the invention relates to a rayon fiber capable of emitting active ions to exhibit an effect of invigoration or activation of living body cells as well as to a method for the preparation thereof.
It is an issue of interest in recent years that living body cells can be activated by so-called active ions to improve the healthful condition of the living body so that various studies are now under way to utilize active ions for the control of autonomic and motorial nervous systems, promotion of sound sleep, ataractic stabilization, acceleration of recovery from fatigue and so on.
As one of the substances which emit such active ions, tourmaline, which is a naturally occurring mineral but can be synthesized artificially, is proposed as promising. Namely, tourmaline is the strongest in the permanent spontaneous electric polarizability among known electret minerals having permanent polarizability so that the vector of polarization thereof is not influenced by an external electric field. It is also noted that the tourmaline mineral emits far-infrared light.
One of the inventors has proposed, directing his attention to these facts, tourmaline-containing electret fibers in Japanese Patent Publication 6-104926 after extensive investigations on the beneficial effects such as improvement of blood circulation on a person wearing clothes or athletic supporters made from a fabric of certain fibers containing fine particles of tourmaline.